May 22, 1919] 



NATURE 



239 



Aristotelian Society, April 15.— Prof. G. D. Hicks in 

 the chair.— Prof. J. B. Baillie : The stereoscopic 

 character of knowledge. In knowledge the mind 

 seeks to become conscious of the individuality of the 

 object in its solid integrity. In the process of know- 

 ledge the whole energy of the individual mind is 

 engaged, and not simply one particular function. The 

 ultimate achievement of knowledge is the fulfilment 

 or realisation of the individual mind as a single whole 

 of individuality existing and subsisting in interdepend- 

 ence with a world of equally real individual beings. 

 The view of knowledge as consisting in a mere linear 

 succession of stages which are means to and sub- 

 ordinate to an end is' set aside as inaccurate because 

 the end is present in the process from first to last, 

 and because the life of the mind, of which knowing 

 is one mode, grows and maintains itself by the simul- 

 taneous co-operation of all its functions in their in- 

 separable unity. Equally inaccurate, it is held, is the 

 view that in knowledge the mind merefy represents, 

 reproduces, and copies the real world. As contrasted 

 with these views, it is maintained that knowledge is 

 stereoscopic or realistic in character. It is realistic 

 in the sense that it presents the real in its solid 

 integrity, that it is a vital activity in which the 

 individual mind fulfils its own life, and that it is the 

 consummation in conscious form of the nature of the 

 real world as embodied in man's plane of existence. 



Cliallenger Society, April 30.— Prof. E. W. MacBride 

 in the chair. — E. J. Allen : A contribution to the 

 quantitative study of plankton. To determine the 

 number of individual organisms belonging to the 

 smaller Protista which are present in a sample of sea- 

 water, the best method hitherto available has been to 

 subject a small sample of the water to the action of 

 a centrifuge, and then count under the microscope 

 the number of individual cells contained in the 

 deposit. By adding a small quantity {\ c.c.) of the 

 sample of sea-water to be examined to a large quantity 

 {\\ litres) of a suitable sterile culture medium, sub- 

 dividing into a number (70) of small flasks, and allow- 

 ing the organisms in these flasks to develop, the 

 author has shown that a very much larger number 

 of unicellular organisms are present than the centri- 

 fuge method would lead one to suppose. 



Geological Society, May 7.— Mr. G. W. Lamplugh, 

 president, in the chair. — Major R. W. Brock : Geo- 

 logy of Palestine. The following formations are 

 recognised :— 



<)UATERNARV. Allufium. 



Pliocene. 

 Eocene. 



Dunes ; Valley and Plains clay, 



and Silt : Desert Crust. 

 Terrestrial. Lion Formation 

 (Jordan-lake-heds). 

 Marine. Upper Calcareous Sand- 

 stone and Limestone. 

 Lower Calcareous Sand- 

 stone. 

 Lacustrine. 

 Nummulitic Limestone. 



TDanian 

 fSenonian -! Campanian 

 I VSant 



Heavy 



volcanic 

 flows, 

 basalts, 

 ashes, 

 tuffs, etc. 



I volcanics, 



( Wsalts. 



Cretaceous.-, 



r Upper -j 



Tui 

 Cenomanian. 



'Lower Nubian Sandstone. 



JebelUsdum formation (?). 

 Jurassic. On Lebanon and Hermon only. 

 Pal.«ozoic. Carboniferous. Possibly southea.st of the Dead Sea. 



\ Cambrian. Dolomite and sandstone. 



pRK.rAMi.Knv, Volcanics and arkose. 



Red granites and porphyries. 



Grey granites, gneiss, and crystalline schists. 



lilt >Liuiiure was shown to be that of a tableland 

 bisected by a great rift-valley (graben), and flanked 

 by a coastal plain, k section was exhibited illustrat- 

 ing East Jordanland acting as a horst; the boundary 

 faults of the Jordan Trench ; the Unequal sinking of 

 the contained blocks ; the western section of the table. 



WO. ?<H6. VOL. 103] 



land sunken with relation to the eastern, and' thrown 

 into an asymmetric anticline, the limbs of which rise 

 in steps through monoclinal flexures or faults. 



Optical Society, May 8.— Prof. F. J. Cheshire: The 

 polarisation of light. The lecture was illustrated 

 throughout by means of projection apparatus invented 

 and designed by the lecturer, an important feature of 

 the apparatus being the form of polariser in which a 

 modified double-image prism was employed instead 

 of the usual Nicol. It was explained that the spar 

 required for this particular prism was only about one- 

 eighth of that required for a Nicol prism of the same 

 aperture. — J. Rheinberg : -Graticules. Starting with 

 the Origin of the term graticules, which are defined 

 as the " measuring scales or marks placed in the focal 

 plane of an optical instrument for the purpose of 

 determining the size, distance, direction, position, or 

 numbers of the object viewed coincidently with the 

 scale itself," the paper discusses in detail the various 

 methods of manufacture in this country and abroad 

 up to the period of the war, which led to the CS^- 

 mans having a practical monopoly of the article except 

 in the case of simple patterns, such' as cross-lines and 

 simple patterns without numerals. This is followed 

 by some account of the research work done during the 

 war, which led to the production of graticules by the 

 author, first by grainless photography, and ultimately 

 bv filmless photography, enabling graticules to be 

 turned out in large quantities, not only of the kinds 

 hitherto only produced abroad, but also of many new 

 kinds. The optical peculiarities of the various kinds 

 are next discussed, and a chapter deals with graticule 

 design, showing how, with the variety and choice 

 now available, it is necessary to co-ordinate the grati- 

 cule to the design of the optical instrument and its 

 purpose as a whole. A number of new uses for grati- 

 cules are put forward, and it is suggested that new 

 applications, some of which have already been 

 initiated, might easily lead to important improvements 

 in many types of optical apparatus. 



Zoological Society, Miay 13. — Prof. E. W. Mac- 

 Bride, vice-president, in the chair. — N. Taylor : A 

 unique case of asymmetrical duplicit)' in the chick. — 

 Lt.-Col. S. Monckton Copeman : Experiments on sex 

 determination. 



Mathematical Society, May 15.— Mr. J. E. Campbell, 

 president, in the chair.— Prof. G. N. Watson : The 

 zeroes of Lommel's polynomials. — Prof. VV. H. 

 Young : The triangulation method of defining the 

 area of a surface. 



Manchester. 



Literary and Philosophical Society, April 29. — Prof. 

 G. Elliot Smith, president, in the chair.— Sir Henry 

 Miers : Some features in the growth of crystals. 

 Crystals not only change their form during growth by 

 the development of new faces, but also often display 

 a tendency to appear first as needles and then in 

 regular forms, seeming to pass through two stages. 

 Experiments were made by the author many years 

 ago in an attempt to determine the concentration of 

 the solution in contact with a growing crystal, the 

 refractive index being measured by the method of 

 total internal reflection. These experiments led to 

 the conclusion that in a cooling supersaturated solu- 

 tion stirred in an open trough, a sudden change in 

 refractive index takes place at a definite temperature, 

 and that this is due to the sudden appearance of new 

 crvstals or to the suddenlv increased growth of the 

 crvstals already present. Enclosed in a sealed tube 

 and shaken, the solution yields a shower of crystals 

 at this temperature alone," although, for example, in 

 the case of sodium nitrate, it is about 10° below that 

 of saturation. Further experiments on a large 



